<writemark-editor> live inline editor

Dependency-free markdown web component. This demo opens directly from disk or through a local server. Inline/live is the primary editing surface: headings, inline formatting, tables, code blocks, task checkboxes, and lists render inside the editor itself while markdown source remains canonical. Source, split, preview-only, and optional companion-preview modes remain available when a host needs them. There is no built-in toolbar; use Markdown shortcuts, slash commands, keyboard shortcuts, or the public action API.